dm07403.m

the code of the book come form the book of marlix laboratory with the book of singal

%dm07403
%观察连续时间信号的时域变换
syms t; 
f=sym('(t+1)*(heaviside(t+1)-heaviside(t))');
f=f+sym('(heaviside(t)-heaviside(t-1))');    %定义信号符号表达式
ezplot(f,[-3,3])                                 %绘制信号波形
axis([-3,3,-1.2,1.2])
set(gcf,'color','w')
title('f(t)')
pause
f1=subs(f,t,t+1.5);                       %变量替换
ezplot(f1,[-3,3])                        %绘制f(t+1.5)波形
title('f(t+1.5)')
pause
f2=subs(f,t,t-1.5);
ezplot(f2,[-3,3])                       %绘制f(t-1.5)波形   
title('f(t-1.5)')
pause
f3=subs(f,t,-t);
ezplot(f3,[-3,3])                       %绘制f(-t)波形  
title('f(-t)')
pause
f4=-f;
ezplot(f4,[-3,3])                     %绘制-f(t)波形
title('-f(t)')
pause
f5=subs(f,t,(1/2)*t);
ezplot(f5,[-3,3])                        %绘制f(0.5t)波形  
title('f(0.5t)')